In its efforts to always maintain a strong national defense arsenal, the United States has manufactured a number of chemical weapons. Among the most terrifying of these are the so-called "nerve gases". These agents attack cholinesterase, an enzyme which is associated with all neural tissue. They are lethal at very low concentrations, and react very quickly.
Large quantities of these agents are now normally stored by the Army in liquid form for possible use in a future war. However, some of the inventory represents a safety hazard to Army personnel. Some of these gases have been stored for decades in vessels which were not designed for long-term use. Some have deteriorated and are no longer usable. Thus far, efforts to destroy these compounds have been frustrated by the inability of destruction processes to completely destroy the agents.
Insecticides which are based upon substituted or unsubstituted phosphoric and thiophosphoric acid, and especially off-grade products or waste materials generated during the manufacture of these products also present destruction problems. These compounds are also cholinesterase inhibitors, although not as highly toxic as the military nerve gases. Recently, one of these compounds, Parathion, was banned from the marketplace by the Federal government; the existing inventory of this compound, and any waste products generated in its manufacture must be destroyed.
Two methods have been considered for destroying these agents. One of these involves holding them at 1000.degree. F. for a period of fifteen minutes. To accomplish this requires a pressure vessel, and entails a batch-wise process. The other destruction method involves incineration. The incineration process requires not only residence time at or above the ignition temperature, but also requires combustion gases, to provide an excess of oxygen for complete combustion.
These agents contain phosphorus, oxygen, carbon and hydrogen, and can contain nitrogen, sulfur or fluorine. If these compounds are incinerated, the combustion products include not only carbon dioxide and water, which are harmless; but nitric oxides, sulfur oxides, phosphorus oxides and hydrogen fluoride. The combustion gases must be scrubbed clean of these latter products and unreacted agent and unreacted agent accumulated in the scrubber provides a disposal problem. Furthermore, conventional incinerators are not useful since they do not contain means to recapture and recycle the gases. As a result, if some agent passes through the incinerator unaffected, it will be discharged to the environment.